Differences between 5/8" thread?

[gareth]

Evening all, I've just tried fitting my new PES mod which was machined to 5/8"x18 to my Remmy which was threaded by Edgar Bros in house at what I was told 5/8". The mod screws on ok for about half of the thread and then stops. Are there any variations on 5/8" threads and have I cocked up!

 

Thanks, Gareth.

[Ronin]

Gareth

 

5/8 th unf is .625"x18 tpi

 

 

However there are different classes of fit or tightness if you will.

 

Most people who thread for this application do so using class b which in essence is free spinning but not loose fit bettween the male and female parts.

 

The problEm comes when manufacturers make threads to differing tolerances which I think may be the issue here unless there is a piece of swarf in the thread of either par t?

 

If both are clean I suggest that it will be easier to alter the barrel thread than the moddy

 

your dealer should be able to sort you out it may be the case that the thread is too tight and a thou or so needs taking off this would need doing on the lathe I would not recommend using a die as you may lose concrntricity although this is unlikey with pre cut thread ....

[gareth]

Thanks Ronin, all the threads look clean and the mod spins on nicely to start with. I didn't want to force anything (in the land of hamfisted, I am king!) so it looks like I'll have to get the muzzle thread recut to suit. Thanks again, Gareth.

[Ronin]

It could of course be the thread in the can that's wrong if you have a mate with a 5/8 th unf threaded rifle you could see if that fits?

[gareth]

Been to my local gunsmith today and he's sorted it for me. He reckons it was a combination of a tight thread on the mod and the thread on my rifle. He ran a tap through the mod thread and recut and recessed the thread on my rifle a little, all screws together nicely now. The best bit is he didn't charge me, quite unusual for him! ATB, Gareth.

[whoowhoop]

Is this thread size common to Edgar Bros?

I have just bought a 700 S(hitty)P(lastic) S(tock) Varmint and it has 5/8 thread, which is a problem as I wanted to fit A-TEC CMM-4 mod and it doesn't appear to come in that threading.

Ah! Well!

[baldie]

5/8" x 18 unf is probarbly the most common thread fitted to varmint weight barrels there is. I do all our jobs in this format, unless asked specifically for metric. The problem is that most people wont shell out for a set of industry standard, and certified thread ring gauges. They are around £80 each. We have one for every thread size we cut. It means there is no argument from the customer, regarding tight mods etc.....because when its cut to an industry standard....its the mod thats wrong, simple as that. If you have bought the mod from Pete Jackson, he will take it back and supply you with one in this thread.

[whoowhoop]

Thanks for that.

I haven't got the mod yet. Just waiting for response from Jackson Rifles as to whether they can supply an A-TEC to fit.

[whoowhoop]

A-TEC CMM 4 now available in 5/8" thread from Jacksons.

[baldie]

Glad you got sorted. 5/8" unf is almost as common as 1/2" these days, and a better thread on varmint weight barrels.

 

Have a look at this one.

I sold one of our mods to a dealer who complained the gun wouldn,t shoot with it on. It was clipping the mod.

This is a factory supplied thread [supposedly] on a browning A bolt. It has 2 shoulders, neither of which is square, the thread is tapered, and i cut my hand on the end, and BWM , the importer then had the cheek to tell the dealer that i had invalidated the warranty by correcting all this crap.

 

 

We then had a quicksilver delivered last week for a .20 remington. The guy bought the gun from elsewhere, and then expected me to take the responsibility for fitting the mod. Quicksilvers are very tight indeed, on the bore to bullet size ratio, and MUST be fitted EXACTLY. The mod wouldn,t even screw down the thread. The mod,s thread was EXACTLY to spec. The barrel wouldn,t even let the GO gauge start, and this is another "factory " thread.

 

Moral in here guy,s. When the importers are paying pence for a threading job....its not worth a chew of bacca. Pay a decent gunsmith to thread your guns, because these two examples were bordering on unsafe.

[Ronin]

I cannot believe the thread / shoulder in the picture even left the lathe Dave.

 

 

Whoever did that should give up.

 

 

Sorry, but its shxxe

[deerman]

Dave,

 

I get calls from customers on a very regular basis about threading. It is sometimes hard to make people understand the importance of correct threading, as this is the only guarantee that the moderator will fit correctly and alignment will not be compromised.

While on holiday at the end of last year I received a call from a customer in a bit of a panic, as he had bought two Quicksilver titanium moderators - .270 and .308 - and while checking the zero on both rifles he realised that he had shot the .308 rifle with the .270 moderator on. I asked him to send it back for a check. On initial inspection there was nothing wrong with the moderator, but just to be on the safe side I had it opened and checked all the internal components only to find that the .308 round had gone through the 8 baffles without touching a single one or the exit cap. The bore on the .270 moderator is .310" and the .308 bullet is just just that, i.e. .308" in diameter. Because of the precision engineering and perfect alignment in our products, and the excellent thread job by Mike Norris, that moderator wasn't damaged, much to the customer's relief.

 

I think that a section on the forum for recommendations or "to be avoided" would be of great help for those who are considering having a barrel threaded.

 

Best,

 

George

[sauer]

I think that a section on the forum for recommendations or "to be avoided" would be of great help for those who are considering having a barrel threaded.

 

Best,

 

George

 

 

 

HERE HERE !!!!!! definately would be a big help in deciding whom or where to go...not just for threading, but for customer service in general and quality of smithing etc etc.

 

 

perfect example on here on another thread regarding a company going to court and monies lost etc.

 

 

if its good shout bout it!!!!

 

 

sauer / paul

[Ronin]

Not sure its a good idea to name who to go to and whom not to.

 

What could be done is a "what to look for" section - examples of good / bad threads possibly.

 

Perhaps good / bad chambering but I havent a digiscope attachment for my borescope....(and I dont do bad chambering !!!)

 

Good / bad bedding?

 

 

 

Again, not advokating name shame of people, its not fitting for the site, unproffessional and doesn't help relations.

 

 

What do others think?

[Vermincinerator]

I did a thread correction for one of George's customers, it was the most shocking muzzle thread i have ever seen.

Rifle was a very nice Sauer Outback in 308 that had been threaded by a "reputable" shop.

This so called 1/2x20 UNF was .484" diameter, did not have an undercut at all, was torn and had no chamfer on the muzzle end.

The moderator would not butt up against the shoulder but the customers previous mod (T8) went on no problem!!

All i could do was chase the threads form an undercut and make sure the shoulder was perpendicular to the bore, ideally the muzzle should have been re-threaded but due to the fluted barrel, re-threading would have cut into the flutes, something the customer did not want.

I had a photo but my PC crashed last weekend and i have lost all my previous files.

 

Ian

[Ronin]

Hmm

 

.016" undersize, must have been a "lovely" fit

[Vermincinerator]

Believe it or not the fit was not too bad, i reckon whoever did it took the crests off the thread to tart it up a bit.

 

Ian.

[sauer]

i guess you have a good point regarding naming and shaming with regards to the site....

 

but taking the post regarding "global rifles" recently.....im sure glad i have that kinda info now, espicially if i was considering them for a new rifle.

 

 

sauer / paul